Component in processing chamber of substrate processing apparatus and method of measuring temperature of the component

ABSTRACT

A component in a processing chamber of a substrate processing apparatus, where a temperature may be accurately measured by using a temperature measuring apparatus using an interference of a low-coherence light, even when a front surface and a rear surface are not parallel due to abrasion, or the like. A focus ring used in a vacuum atmosphere and of which a temperature is measured includes an abrasive surface exposed to an abrasive atmosphere according to plasma, a nonabrasive surface not exposed to the abrasive atmosphere, a thin-walled portion including a top surface and a bottom surface that are parallel to each other, and a coating member coating the top surface of the thin-walled portion, wherein a mirror-like finishing is performed on each of the top and bottom surfaces of the thin-walled portion.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of Japanese Patent Application No.2011-069838 filed on Mar. 28, 2011, in the Japan Patent Office and U.S.patent Application Ser. No. 61/472,688 filed on Apr. 7, 2011, in theUnited States Patent Trademark Office, the disclosure of which areincorporated herein in their entireties by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a component in a processing chamber ofa substrate processing apparatus, and a method of measuring atemperature of the component.

2. Description of the Related Art

In a substrate processing apparatus for performing a predeterminedplasma process on a wafer constituting a substrate by using plasmagenerated in a processing chamber, members disposed in the processingchamber are worn away by the plasma. Specifically, an abrasion loss of afocus ring disposed to surround the wafer and formed of the samematerial as the wafer is high as the focus ring is exposed to plasmahaving relatively high density. Since a distribution of plasma on thewafer changes when the focus ring is worn away, the focus ring needs tobe replaced when the abrasion loss of the focus ring exceeds apredetermined amount while monitoring the abrasion loss.

Also, conventionally, when various processes, such as a plasma process,are performed on the wafer, temperatures of the wafer and each componentin the processing chamber are measured and controlled so as to promotecertainty of a process. In addition, recently, technologies about atemperature measuring method that measures a temperature of a focus ringby using a low-coherence light interference thermometer have beensuggested (for example, refer to Patent References 1 and 2). Thelow-coherence light interference thermometer measures a temperature of atarget by irradiating a low-coherence light toward a rear surface of thetemperature measured target, for example, a focus ring, and measuringinterference between a reference light and reflection lights from afront surface and the rear surface.

However, in a temperature measuring technology using a low-coherencelight interference thermometer, a measured target should satisfyrequirements, such as allowing a part of a measurement light topenetrate therethrough, having a high degree of parallelization of afront surface and a rear surface at a measurement portion, and having amirror-like finished front surface and rear surface. Accordingly, whenthe measured target is worn away by plasma and the degree ofparallelization of the surface and rear surface is no longer maintained,requirements of the measured target are not satisfied, and thus atemperature cannot be accurately measured.

Also, conventional suggestions about a temperature measuring technologyusing a low-coherence light interference thermometer are mainly aboutimproving a low-coherence light interference thermometer, and studiesabout making a measured target suitable for temperature measurementusing a low-coherence light interference thermometer have not beenperformed.

-   (Patent Document 1) Japanese Laid-Open Patent Publication No.    2008-227063-   (Patent Document 2) Japanese Laid-Open Patent Publication No.    2003-307458

SUMMARY OF THE INVENTION

The present invention provides a component in a processing chamber of asubstrate processing apparatus and a method of measuring a temperatureof the component, where a temperature is accurately measured by using atemperature measuring apparatus using an interference of a low-coherencelight, even when a front surface and a rear surface are not parallel dueto abrasion, or the like.

According to an aspect of the present invention, there is provided acomponent in a processing chamber of a substrate processing apparatus,wherein a temperature of the component is measured, the componentincluding: an abrasive surface which is exposed to an abrasiveatmosphere and a nonabrasive surface which is not exposed to theabrasive atmosphere; a temperature measured portion including a surfaceat the abrasive surface side and a surface at the nonabrasive surfaceside, which are parallel to each other; and a coating portion whichcoats the surface of the temperature measured portion at the abrasivesurface side.

The temperature measured portion may be a thin-walled portioncorresponding to a concave portion formed on the abrasive surface, and amirror-like finishing may be performed on each of a surface of thethin-walled portion at the abrasive surface side and a surface of thethin-walled portion at the nonabrasive surface side.

A surface roughening process may be performed on a surface of thecoating portion facing the surface of the thin-walled portion at theabrasive surface side.

A heat transfer sheet or a heat transfer gas may be disposed at acontact portion of the coating portion and an inner surface of theconcave portion.

The coating portion may be formed of any one of silicon (Si), siliconcarbide (SiC), quartz, sapphire, ceramic, alumina (Al₂O₃), and aluminumnitride (AlN).

The temperature measured portion may be a temperature measured memberinserted to a concave portion formed on the nonabrasive surface of thecomponent in the processing chamber of the substrate processingapparatus, wherein a mirror-like finishing may be performed on each of asurface of the temperature measured member at the abrasive surface sideand a surface of the temperature measured member at the nonabrasivesurface side.

A surface roughening process may be performed on an inner surface of theconcave portion facing the surface of the temperature measured member atthe abrasive surface side.

A heat transfer sheet or a heat transfer gas may be disposed at acontact portion of the temperature measured member and the inner surfaceof the concave portion.

The temperature measured member may be formed of silicon (Si), quartz,or sapphire.

The temperature measured portion may be a part of the component in theprocessing chamber of the substrate processing apparatus, a mirror-likefinishing may be performed on each of the surface at the abrasivesurface side and the surface at the nonabrasive surface side withrespect to the part of the component in the processing chamber of thesubstrate processing apparatus, and the surface at the abrasive surfaceside, on which the mirror-like finishing is performed, may be covered bythe coating portion.

The temperature measured portion may be a temperature measured memberengaged to a cut-out portion formed on the nonabrasive surface of thecomponent in the processing chamber of the substrate processingapparatus, a mirror-like finishing may be performed on each of thesurface of the temperature measured member at the abrasive surface sideand the surface of the temperature measured member at the nonabrasivesurface side, and the surface of the temperature measured member at theabrasive surface side may be covered by a part forming the cut-outportion of the component in the processing chamber of the substrateprocessing apparatus.

The temperature measured portion may be a temperature measured memberattached to the nonabrasive surface of the component in the processingchamber of the substrate processing apparatus, a mirror-like finishingmay be performed on each of the surface of the temperature measuredmember at the abrasive surface side and the surface of the temperaturemeasured member at the nonabrasive surface side, and the surface of thetemperature measured member at the abrasive surface side may be coveredby the component in the processing chamber of the substrate processingapparatus.

The temperature measured member may have a stepped portion including athick plate portion and a thin plate portion, a surface of the thinplate portion at the abrasive surface side and a surface of the thinplate portion at the nonabrasive surface side may be parallel to eachother, a mirror-like finishing may be performed on each of the surfacesof the thin plate portion, and the surface of the thin plate portion atthe abrasive surface side may be covered by a part of the component inthe processing chamber of the substrate processing apparatus.

The temperature measured member may include a stepped portion includinga thick plate portion and a thin plate portion, a surface of the thickplate portion at the abrasive surface side and a surface of the thickplate portion at the nonabrasive surface side may be parallel to eachother, a mirror-like finishing may be performed on each of the surfacesof the thick plate portion, and the surface of the thick plate portionat the abrasive surface side may be covered by a part of the componentin the processing chamber of the substrate processing apparatus.

The component in the processing chamber of the substrate processingapparatus may be any one of a focus ring, an upper electrode, a lowerelectrode, an electrode protecting member, an insulator, an insulationring, an observation window, a bellows cover, a baffle plate, and adeposhield.

According to another aspect of the present invention, there is provideda method of measuring a temperature of a component in a processingchamber of a substrate processing apparatus by using an interference ofa low-coherence light, the method including: irradiating a measurementlight to a surface of a temperature measured portion at a nonabrasivesurface side, wherein the temperature measured portion is formed in thecomponent in the processing chamber of the substrate processingapparatus, the component including an abrasive surface exposed to anabrasive atmosphere and the nonabrasive surface not exposed to theabrasive atmosphere, a surface of the temperature measured portion atthe abrasive surface side and the surface of the temperature measuredportion at the nonabrasive surface side are parallel to each other, andthe surface of the temperature measured portion at the abrasive surfaceside is covered by a coating portion; receiving a reflection light ofthe measurement light reflected from the surface of the temperaturemeasured portion at the nonabrasive surface side, and a reflection lightof the measurement light reflected from the surface of the temperaturemeasured portion at the abrasive surface side; detecting an optical pathlength difference between the two received reflection lights; andcalculating a temperature of the temperature measured portion based onthe detected optical path length difference and a pre-obtainedrelationship between the optical path length difference and atemperature of the temperature measured portion.

The temperature measured portion may be a thin-walled portioncorresponding to a concave portion formed on the abrasive surface of thecomponent in the processing chamber of the substrate processingapparatus, and a mirror-like finishing may be performed on each of asurface of the thin-walled portion at the abrasive surface side and asurface of the thin-walled portion at the nonabrasive surface side.

A surface roughening process may be performed on a surface of thecoating portion facing the surface of the thin-walled portion at theabrasive surface side.

A heat transfer sheet or a heat transfer gas may be disposed at acontact portion of the coating portion and an inner surface of theconcave portion.

The coating portion may be formed of any one of silicon (Si), siliconcarbide (SiC), quartz, sapphire, ceramic, alumina (Al₂O₃), and aluminumnitride (AlN).

The temperature measured portion may be a temperature measured memberinserted to a concave portion formed on the nonabrasive surface of thecomponent in the processing chamber of the substrate processingapparatus, and a mirror-like finishing may be performed on each of asurface of the temperature measured member at the abrasive surface sideand a surface of the temperature measured member at the nonabrasivesurface side.

A surface roughing process may be performed on an inner surface of theconcave portion facing the surface of the temperature measured member atthe abrasive surface side.

A heat transfer sheet or a heat transfer gas may be disposed at acontact portion of the temperature measured member and the inner surfaceof the concave portion.

The temperature measured member may be formed of silicon (Si), quartz,or sapphire.

The component in the processing chamber of the substrate processingapparatus may be any one of a focus ring, an upper electrode, a lowerelectrode, an electrode protecting member, an insulator, an insulationring, an observation window, a bellows cover, a baffle plate, and adeposhield.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a cross-sectional view schematically showing a configurationof a substrate processing apparatus to which a component in a processingchamber, according to an embodiment of the present invention, isapplied;

FIG. 2 is a block diagram schematically showing a configuration of amember temperature measuring apparatus included in the substrateprocessing apparatus of FIG. 1;

FIG. 3 is a diagram for describing a temperature measuring operation ofa low-coherence light optical system of FIG. 2;

FIGS. 4A and 4B are graphs showing interference waveforms between areflection light from a temperature measured portion of a focus ringdetected by a photo detector (PD) of FIG. 3, and a reflection light froma reference mirror, where FIG. 4A shows interference waveforms obtainedbefore a temperature change of the focus ring and FIG. 4B showsinterference waveforms obtained after the temperature change of thefocus ring;

FIGS. 5A through 5C are views schematically showing a configuration of afocus ring according to a first embodiment of the present invention,wherein FIG. 5A is a plan view, FIG. 5B is a cross-sectional view takenalong a line A-A of FIG. 5A, and FIG. 5C is a cross-sectional view of acoating member inserted into a thin-walled portion;

FIG. 6 is a cross-sectional view schematically showing a configurationof a focus ring according to a modified example of the first embodiment;

FIG. 7 is a cross-sectional view schematically showing a configurationof a focus ring according to a second embodiment of the presentinvention;

FIG. 8 is a cross-sectional view schematically showing a configurationof a focus ring according to a modified example of the secondembodiment;

FIG. 9 is a cross-sectional view schematically showing a configurationof a focus ring according to a third embodiment of the presentinvention;

FIG. 10 is a cross-sectional view schematically showing a configurationof a focus ring according to a modified example of the third embodiment;

FIG. 11 is a cross-sectional view schematically showing a configurationof a focus ring according to a fourth embodiment of the presentinvention; and

FIG. 12 is a cross-sectional view schematically showing a configurationof a focus ring according to a modified example of the fourthembodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described withreference to accompanying drawings.

First, a substrate processing apparatus to which a component in aprocessing chamber, according to an embodiment of the present invention,is applied will be described.

FIG. 1 is a cross-sectional view schematically showing a configurationof a substrate processing apparatus 10 to which a component in aprocessing chamber 15, according to an embodiment of the presentinvention, is applied. The substrate processing apparatus 10 performs aplasma etching process on a wafer for forming semiconductor devices(hereinafter, simply referred to as “wafer”) as a substrate.

Referring to FIG. 1, the substrate processing apparatus 10 includes achamber 11 for receiving a wafer W having a diameter of, for example,300 mm, and a susceptor 12 formed as a cylinder on which the wafer W forsemiconductor devices is placed is disposed in the chamber 11. In thesubstrate processing apparatus 10, a side exhaust passage 13 is formedby an inner side wall of the chamber 11 and a side surface of thesusceptor 12. An exhaust plate 14 is disposed at an intermediate portionof the side exhaust passage 13.

The exhaust plate 14 is formed as a plate-shaped member having aplurality of through-holes, and functions as a partition plate thatdivides an inside of the chamber 11 into an upper portion and a lowerportion. Plasma is generated in the upper portion (hereinafter, referredto as a “processing chamber 15”) of the chamber 11, which is divided bythe exhaust plate 14, as will be described later. In addition, anexhaust pipe 17 for discharging a gas in the chamber 11 is connected tothe lower portion (hereinafter, referred to as an “exhaust chamber(manifold) 16”) in the chamber 11. The exhaust plate 14 captures orreflects plasma generated in the processing chamber 15 to prevent theplasma from leaking to the manifold 16.

A turbo molecular pump (TMP) and a dry pump (DP) (both not shown) areconnected to the exhaust pipe 17, and the TMP and the DP depressurizethe inside of the chamber 11 through a vacuum suction. In more detail,the DP depressurizes the inside of the chamber 11 from atmosphericpressure to a medium vacuum state (for example, less than or equal to1.3×10 Pa (0.1 Torr)), and the TMP depressurizes the inside of thechamber 11 to a high vacuum state (for example, less than or equal to1.3×10⁻³ Pa (1.0×10⁻⁵ Torr)) that is at a lower pressure than the mediumvacuum state, in cooperation with the DP. In addition, the pressure inthe chamber 11 is controlled by an automatic pressure control (APC)valve (not shown).

A first high frequency power source 18 is connected to the susceptor 12in the chamber 11 via a first matcher 19 and a second high frequencypower source 20 is connected to the susceptor 12 via a second matcher21. The first high frequency power source 18 applies a high frequencypower of a relatively low frequency, for example, 2 MHz, to thesusceptor 12 for ion implantation, and the second high frequency powersource 20 applies a high frequency power of a relatively high frequency,for example, 60 MHz, to the susceptor 12 for generating plasma.Accordingly, the susceptor 12 operates as an electrode. In addition, thefirst matcher 19 and the second matcher 21 reduce reflection of the highfrequency powers by the susceptor 12, thereby increasing efficiency ofapplying the high frequency powers to the susceptor 12.

An upper portion of the susceptor 12 has a shape wherein a circumferencehaving a relatively small diameter protrudes along a concentric axisfrom a leading end of a circumference having a relatively largediameter, and a step is formed on the upper portion to surround thecircumference having the relatively small diameter. An electrostaticchuck 23 formed of ceramic and including an electrostatic electrodeplate 22 therein is disposed on a leading end of the circumferencehaving the relatively small diameter. A direct current power source 24is connected to the electrostatic electrode plate 22. When a positivedirect current voltage is applied to the electrostatic electrode plate22, negative electric potential is generated on a surface of the wafer Wat the electrostatic chuck 23 side (hereinafter, referred to as a “rearsurface”), and thus an electric field is generated between theelectrostatic electrode plate 22 and the rear surface of the wafer W.Then, the wafer W is adhered and held against the electrostatic chuck 23by Coulomb force or Johnson-Rahbek force caused by the electric field.

In addition, on an upper portion of the susceptor 12, a focus ring 25(the component in the processing chamber) is placed on the step of thesusceptor 12 so as to surround the wafer W adhered by and held againstthe electrostatic chuck 23. The focus ring 25 is formed of, for example,silicon (Si).

The focus ring 25 is an annular shaped member, and includes a topsurface 25 a (abrasive surface) exposed inside the processing chamber15, and a bottom surface 25 b (nonabrasive surface) facing the step ofthe susceptor 12. Also, the focus ring 25 includes a thin-walled portion25T as a temperature measured portion (refer to FIG. 5 described below).A surface (hereinafter, referred to as a “top surface”) 25Ta of thethin-walled portion 25T at the abrasive surface side and a surface(hereinafter, referred to as a “bottom surface”) 25Tb of the thin-walledportion 25T at the nonabrasive surface side are parallel to each other.

A shower head 26 is disposed at a ceiling portion of the chamber 11 toface the susceptor 12. The shower head 26 includes an upper electrodeplate 27, a cooling plate 28 that detachably hangs and supports theupper electrode plate 27, and a lid 29 covering the cooling plate 28.The upper electrode plate 27 is a disc shaped member having a pluralityof gas holes 30 penetrating through the upper electrode plate 27 in athickness direction, and is formed of silicon constituting asemiconductor.

A buffer chamber 31 is formed inside the cooling plate 28, and aprocessing gas introducing pipe 32 is connected to the buffer chamber31.

In the substrate processing apparatus 10, a processing gas that issupplied into the buffer chamber 31 through the processing gasintroducing pipe 32 is introduced into the inner space of the processingchamber 15 via the gas holes 30. The introduced processing gas isexcited by the high frequency power for generating plasma, which isapplied in the inner space of the processing chamber 15 via thesusceptor 12 from the second high frequency power source 20, and becomesplasma. Ions in the plasma are attracted by the high frequency power forion implantation, which is applied from the first high frequency powersource 18 to the susceptor 12, toward the wafer W, and then a plasmaetching process is performed on the wafer W. Here, the ions in theplasma also reach and sputter the top surface 25 a of the focus ring 25or a bottom surface of the upper electrode plate 27.

Such a substrate processing apparatus 10 includes a member temperaturemeasuring apparatus so as to measure a temperature of a component in theprocessing chamber, such as the focus ring 25. FIG. 2 is a block diagramschematically showing a configuration of a member temperature measuringapparatus 33 included in the substrate processing apparatus 10 ofFIG. 1. Hereinafter, the member temperature measuring apparatus 33included in the substrate processing apparatus 10, and a temperaturemeasuring method using a low-coherence light performed by the membertemperature measuring apparatus 33 are described with reference to FIGS.2 through 4, but the member temperature measuring apparatus 33 and thetemperature measuring method are only examples, and are not limitedthereto.

Referring to FIG. 2, the member temperature measuring apparatus 33includes a low-coherence light optical system 34 that irradiates alow-coherence light, for example, to the focus ring 25 in the substrateprocessing apparatus 10, and receives a reflection light of thelow-coherence light, and a temperature calculating apparatus 35 thatcalculates a temperature of the focus ring 25 based on the reflectionlight received by the low-coherence light optical system 34. Alow-coherence light is a light where it is difficult for wave trains ofat least two lights divided from a light irradiated from one lightsource to overlap as the at least two lights travel relatively far (itis difficult for the at least two lights to interfere with each other),and has a relatively short coherence distance (coherence length).

The low-coherence light optical system 34 includes a super luminescentdiode (SLD) 36 as a low-coherence light source, an optical fiber fusioncoupler (hereinafter, simply referred to as a “coupler”) 37 operating asa 2×2 splitter connected to the SLD 36, collimators 38 and 39 connectedto the coupler 37, a photo detector (PD) 40 as a light-receiving deviceconnected to the coupler 37, and optical fibers 41 a, 41 b, 41 c, and 41d connecting each component.

The SLD 36 irradiates, for example, a low-coherence light having acenter wavelength of 1.55 μm or 1.31 μm and a coherence length of 50 μm,at a maximum output of 1.5 mW. The coupler 37 divides the low-coherencelight from the SLD 36 into two low-coherence lights, and transmits thetwo low-coherence lights respectively to the collimators 38 and 39through the optical fibers 41 b and 41 c. The collimators 38 and 39 arerespectively a collimator that irradiates the two low-coherence lights(a measurement light 50 and a reference light 51 described below), whichare divided by the coupler 37, perpendicularly to the bottom surface25Tb of the thin-walled portion 25T constituting the temperaturemeasured member of the focus ring 25, and a collimator that irradiatesthe two low-coherence lights perpendicularly to a reflection surface ofa reference mirror 42 described below. Also, the PD 40 is formed of, forexample, a germanium (Ge) photo diode.

The low-coherence light optical system 34 includes the reference mirror42 disposed in front of the collimator 39, a reference mirror drivingstage 44 for horizontally moving the reference mirror 42 by using aservo motor 43 so as to follow an irradiation direction of thelow-coherence light from the collimator 39, a motor driver 45 fordriving the servo motor 43 of the reference mirror driving stage 44, andan amplifier 46 for amplifying an output signal from the PD 40 by beingconnected to the PD 40. The reference mirror 42 may be a corner cubeprism or plane mirror having a reflection surface.

The collimator 38 is embedded in the susceptor 12 to face the bottomsurface 25Tb of the thin-walled portion 25T with respect to the focusring 25, and irradiates the low-coherence light (the measurement light50 described below) obtained through the coupler 37 to the bottomsurface 25Tb of the thin-walled portion 25T while receiving reflectionlights (a reflection light 52 b and a reflection light 52 a describedbelow) of the low-coherence lights from the bottom and top surfaces 25Tband 25Ta of the thin-walled portion 25T and transmitting the reflectionlights to the PD 40.

The collimator 39 irradiates the low-coherence light (the referencelight 51 described below) obtained by the coupler 37 to the referencemirror 42 while receiving a reflection light (a reflection light 54described below) of the low-coherence light from the reference mirror 42and transmitting the reflection light to the PD 40.

The reference mirror driving stage 44 horizontally moves the referencemirror 42 in a direction indicated by an arrow A shown in FIG. 2, suchthat the reflection surface of the reference mirror 42 is alwaysperpendicular to an irradiated light from the collimator 39. Thereference mirror 42 may move back and forth along the directionindicated by the arrow A. Also, in FIG. 2, the irradiated light from thecollimator 39 and the reflection light from the reference mirror 42 areshown to each have a predetermined direction angle so as not to overlapeach other for convenience of description, but needless to say, theyactually overlap each other without having the predetermined directionangle. The same is applied to the collimator 38 or a laserinterferometer 48 a described below.

The temperature calculating apparatus 35 includes a personal computer(PC) 47 that controls the entire temperature calculating apparatus 35, amotor controller 48 that controls the servo motor 43 for moving thereference mirror 42 via the motor driver 45, and an analog/digital (ND)converter 49 that performs an analog-to-digital conversion by beingsynchronized to a control signal from the laser interferometer 48 a.Here, if a distance of the reference mirror 42 is accurately measured bythe laser interferometer 48 a or a linear scale (not shown), the NDconverter 49 performs an ND conversion on an output signal of the PD 40via the amplifier 46 of the low-coherence light optical system 34 bybeing synchronized to a control signal according to a moving distancemeasured by the laser interferometer 48 a or the linear scale, therebymeasuring a temperature at a high precision.

FIG. 3 is a diagram for describing a temperature measuring operation ofthe low-coherence light optical system 34 of FIG. 2.

The low-coherence light optical system 34 is an optical system using alow-coherence interferometer having a Michelson interferometer as abasic structure. As shown in FIG. 3, a low-coherence light irradiatedfrom the SLD 36 is split into the measurement light 50 and the referencelight 51 by the coupler 37 operating as a splitter, wherein themeasurement light 50 is irradiated toward the thin-walled portion 25T ofthe focus ring 25 constituting a measured target, and the referencelight 51 is irradiated toward the reference mirror 42.

The measurement light 50 irradiated to the thin-walled portion 25T ofthe focus ring 25 is reflected at each of the bottom surface 25Tb andthe top surface 25Ta of the thin-walled portion 25T, and the reflectionlight 52 b from the bottom surface 25Tb of the thin-walled portion 25Tand the reflection light 52 a from the top surface 25Ta of thethin-walled portion 25T are incident on the coupler 37 through an sameoptical path 53. Also, the reference light 51 irradiated to thereference mirror 42 is reflected at the reflective surface, and thereflection light 54 from the reflection surface is also incident on thecoupler 37. Here, as described above, since the reference mirror 42moves horizontally according to the irradiation direction of thereference light 51, the low-coherence light optical system 34 may changeoptical path lengths of the reference light 51 and the reflection light54.

The reflection light 52 b and the reflection light 54 interfere witheach other when the optical path lengths of the reference light 51 andthe reflection light 54 are changed such that optical path lengths ofthe measurement light 50 and the reflection light 52 b are the same asthe optical path lengths of the reference light 51 and the reflectionlight 54. Also, the reflection light 52 a and the reflection light 54interfere with each other when the optical path lengths of themeasurement light 50 and the reflection light 52 a are the same as theoptical path lengths of the reference light 51 and the reflection light54. Such interference is detected by the PD 40. Upon detecting theinterference, the PD 40 outputs a signal.

FIGS. 4A and 4B are graphs showing interference waveforms between areflection light from the thin-walled portion 25T (the temperaturemeasured portion) of the focus ring 25 detected by the PD 40 of FIG. 3,and a reflection light from the reference mirror 42, where FIG. 4A showsinterference waveforms obtained before a temperature change of the focusring 25 and FIG. 4B shows interference waveforms obtained after thetemperature change of the focus ring 25. Also, a vertical axis denotesinterference intensity and a horizontal axis denotes a distance of thereference mirror 42 horizontally moved from a predetermined startingpoint (hereinafter, simply referred to as a “reference mirror movementdistance”).

As shown in the graph of FIG. 4A, when the reflection light 54 from thereference mirror 42 interferes with the reflection light 52 b from thebottom surface 25Tb of the thin-walled portion 25T of the focus ring 25,for example, an interference waveform 55 based on an interferencelocation A is detected. Also, when the reflection light 54 from thereference mirror 42 interferes with the reflection light 52 a from thetop surface 25Ta of the thin-walled portion 25T of the focus ring 25,for example, an interference waveform 56 based on an interferencelocation B is detected. Since the interference location A corresponds tooptical path lengths of the measurement light 50 to the bottom surface25Tb of the thin-walled portion 25T and the reflection light 52 b, andthe interference location B corresponds to optical path lengths of themeasurement light 50 to the top surface 25Ta of the thin-walled portion25T and the reflection light 52 a, a difference D between theinterference locations A and B corresponds to an optical path length ofa low-coherence light (a part of the measurement light 50 and thereflection light 52 a) that moves back and forth in a thicknessdirection within the thin-walled portion 25T of the focus ring 25. Sincethe optical path length of the low-coherence light that moves back andforth in the thickness direction within the thin-walled portion 25Tcorresponds to a thickness of the thin-walled portion 25T, thedifference D of the interference locations A and B corresponds to thethickness of the thin-walled portion 25T. In other words, the thicknessof the focus ring 25 may be measured by detecting the interferencewaveforms of the reflection light 54 and reflection light 52 b and ofthe reflection light 54 and reflection light 52 a.

Here, since the thickness of the focus ring 25 changes when thetemperature of the focus ring 25 is changed, the thickness of thethin-walled portion 25T constituting a part of the focus ring 25 is alsochanged, and the optical path lengths of the measurement light 50 to thetop surface 25Ta of the thin-walled portion 25T and the reflection light52 a are changed. In other words, when the temperature of the focus ring25 is changed, the thickness of the thin-walled portion 25T is changed,and thus the interference location B of the reflection light 54 and thereflection light 52 a is changed from the interference location B shownin FIG. 4A. In detail, the interference location B of FIG. 4A is movedto an interference location B′ shown in FIG. 4B. Accordingly, a changedamount of the difference D of the interference locations A and Bcorresponds to an expansion amount accompanied by the temperature changeof the focus ring 25. The member temperature measuring apparatus 33obtains the temperature change from a pre-determined referencetemperature of the focus ring 25 based on the changed amount of thedifference D of the interference locations A and B, and calculates adetected temperature based on the temperature change and the referencetemperature.

Next, a component in a processing chamber of a substrate processingapparatus and a method of measuring a temperature of the component,according to embodiments of the present invention, are described.

FIGS. 5A through 5C are views schematically showing a configuration ofthe focus ring 25 according to a first embodiment of the presentinvention, wherein FIG. 5A is a plan view, FIG. 5B is a cross-sectionalview taken along a line A-A of FIG. 5A, and FIG. 5C is a cross-sectionalview of a coating member 25 d inserted onto the thin-walled portion 25T.

Referring to FIGS. 5A through 5C, the focus ring 25 includes thethin-walled portion 25T as a temperature measured portion. Thethin-walled portion 25T is a thin-walled portion corresponding to aconcave portion 25 c formed on the top surface 25 a of the focus ring 25exposed to an abrasive atmosphere in an upper space (the processingchamber 15) of the chamber 11, and forms a part of the focus ring 25.The top surface 25Ta and the bottom surface 25Tb of the thin-walledportion 25T are parallel to each other, and a mirror-like finishing isperformed on each of the top and bottom surfaces 25Ta and 25Tb. Also,the thin-walled portion 25T is of a constituent material of the focusring 25 since the thin-walled portion 25T is a part of the focus ring25. For example, the thin-walled portion 25T is formed of silicon (Si),and allows a low-coherence light constituting a measurement light topenetrate therethrough. Accordingly, the thin-walled portion 25T issuitable as a temperature measured portion using a low-coherence light.

The thin-walled portion 25T includes the coating member 25 d coating thetop surface 25Ta thereof (refer to FIG. 5C). Accordingly, the topsurface 25Ta is protected from an abrasive atmosphere with plasma. Thecoating member 25 d is formed of, for example, any one of silicon (Si),silicon carbide (SiC), quartz, sapphire, ceramic, alumina (Al₂O₃), andaluminum nitride (AlN), and a thickness thereof is not specificallylimited as long as the top surface 25Ta of the thin-walled portion 25Tis protected from being worn away.

Next, a method of measuring a temperature of the focus ring 25 by usingthe member temperature measuring apparatus 33 of FIG. 2 will bedescribed.

According to the method of the present embodiment, a low-coherence lightis irradiated perpendicularly from the collimator 38 to the bottomsurface 25Tb of the thin-walled portion 25T of the focus ring 25, andreflection lights of the low-coherence light are received from thebottom surface 25Tb and the top surface 25Ta (refer to FIG. 5C). Also, alow-coherence light is perpendicularly irradiated from the collimator 39to the reference mirror 42, and a reflection light from the reflectionmirror 42 is received (refer to FIG. 2).

Here, when interference waveforms between the two reflection lights fromthe thin-walled portion 25T and the reflection light 54 from thereference mirror 42 are observed, the interference waveform 55 generatedas the reflection light 54 from the reference mirror 42 interferes withthe reflection light 52 b from the bottom surface 25Tb of thethin-walled portion 25T, and the interference waveform 56 generated asthe reflection light 54 from the reference mirror 42 interferes with thereflection light 52 a from the top surface 25Ta of the thin-walledportion 25T are detected as described above with reference to FIGS. 4Aand 4B. The changed amount of the difference D between the interferencelocation A of the interference waveform 55 and the interference locationB of the interference waveform 56 corresponds to the expansion amount ofthe thin-walled portion 25T in the thickness direction accompanied bythe temperature change of the thin-walled portion 25T. Accordingly, thetemperature of the thin-walled portion 25T, and furthermore, thetemperature of the focus ring 25, may be calculated based on acorrelation between the expansion amount and the temperature change.

According to the present embodiment, since the focus ring 25 having theabrasive surface (top surface 25 a) exposed to an abrasive atmosphereand the nonabrasive surface (bottom surface 25 b) not exposed to theabrasive atmosphere includes the thin-walled portion 25T having the topsurface 25Ta and the bottom surface 25Tb parallel to each other, and thecoating member 25 d coating the top surface 25Ta of the thin-walledportion 25T, the temperature of the thin-walled portion 25T, andfurthermore, the temperature of the focus ring 25, may be accuratelymeasured without an effect of abrasion, by irradiating a low-coherencelight to the thin-walled portion 25T covered by the coating member 25 dand thus is not worn away.

In the present embodiment, a surface roughening process may be performedon a surface of the coating member 25 d facing the top surface 25Ta ofthe thin-walled portion 25T. Accordingly, a low-coherence light thatreached the coating member 25 d through the focus ring 25 isdiffused-reflected at the coating member 25 d, and thus the PD 40 of themember temperature measuring apparatus 33 does not receive a reflectionlight from the coating member 25 d. As a result, a reflection light isprevented from being unnecessarily received, thereby improvingmeasurement precision. The surface roughening process is performed via,for example, a sandblast method. Here, a surface roughness of thesurface of the coating member 25 d facing the thin-walled portion 25T,which has been surface-roughened, may be, for example, equal to or morethan ¼ of a wavelength of a low-coherence light, i.e., equal to or morethan 0.27 μm (equal to or more than ¼ of 1.05 μm). Accordingly, diffusedreflection of a low-coherence light may be increased to prevent ameasurement error. A light reflection preventing film may be adheredinstead of performing the surface roughening process.

In the present embodiment, a heat transfer sheet may be disposed on anattached surface of the coating member 25 d and the concave portion 25c. Accordingly, continuity of the temperature of the focus ring 25 maybe maintained, and an adverse effect caused as the coating member 25 dis not thermally adhered to an inner wall surface of the concave portion25 c, for example, deterioration of measurement precision, may beprevented.

In the present embodiment, a diameter of the thin-walled portion 25T asa temperature measured portion, i.e., an opening diameter of the concaveportion 25 c, is, for example, equal to or more than 1 mm φ. Thediameter of the thin-walled portion 25T is not limited as long as anarea of the thin-walled portion 25T can have a spot of an irradiatedlight pass therethrough, and a size of the coating member 25 d may be asize for protecting the thin-walled portion 25T as a temperaturemeasured portion from an abrasive atmosphere with plasma.

In the present embodiment, the thickness of the thin-walled portion 25Tdefined by the top surface 25Ta and the bottom surface 25Tb of thethin-walled portion 25T may be equal to or more than 50 μm. Accordingly,overlapping of an interference waveform based on a reflection light fromthe top surface 25Ta of the thin-walled portion 25T and an interferencewaveform based on a reflection light from the bottom surface 25Tb isprevented, and thus measurement precision is improved. Since a coherencelength of a low-coherence light used in the present embodiment is 50 μm,if the thickness of the thin-walled portion 25T, where a mirror-likefinishing is performed on both of the top surface 25Ta and the bottomsurface 25Tb, is lower than 50 μm, it is difficult to identify thereflection light from the top surface 25Ta of the thin-walled portion25T and the reflection light from the bottom surface 25Tb, and thusmeasurement precision may be deteriorated.

In the present embodiment, a focus ring is applied as a component in aprocessing chamber of a substrate processing apparatus, but thecomponent in the processing chamber may be, for example, an upperelectrode, a lower electrode, an electrode protecting member, aninsulator, an insulation ring, an observation window, a bellows cover, abaffle plate, or a deposhield, besides the focus ring.

In the present embodiment, the thin-walled portion 25T is formed as atemperature measured portion, but instead of forming a thin-walledportion, a part of the abrasive surface (top surface 25 a) of the focusring 25 may be a temperature measured portion, a part of a front surfaceand a rear surface of the focus ring 25 may be formed to be parallel toeach other while performing a mirror-like finishing thereto, and a covermember covering the part of the abrasive surface (top surface 25 a) maybe formed.

FIG. 6 is a cross-sectional view schematically showing a structure ofthe focus ring 25 according to a modified example of the firstembodiment. In FIG. 6, a temperature measured portion 25T′ is a part ofthe focus ring 25, and is covered by a coating member 25 d′.

In the modified example of the present embodiment, a low-coherence lightis perpendicularly irradiated to a bottom surface of the temperaturemeasured portion 25T′ like in the embodiment of FIG. 5, and atemperature is measured in the same manner, and thus the same effect maybe obtained. Also, in the modified example of the present embodiment, athickness of the temperature measured portion 25T′ may be equal to ormore than 50 μm. Accordingly, overlapping of an interference waveformbased on a reflection light from a top surface of the temperaturemeasured portion 25T′ and an interference waveform based on a reflectionlight from the bottom surface is prevented, and thus accuratetemperature measurement is possible.

Next, a second embodiment of the present invention will be described.

FIG. 7 is a cross-sectional view schematically showing a structure of afocus ring 65 according to a second embodiment of the present invention.In the focus ring 65, a temperature measured member 65T is buried in abody of the focus ring 65, and is covered by a part of the focus ring65, and thus is protected from an abrasive atmosphere with plasma.

Referring to FIG. 7, the focus ring 65 is formed of, for example,silicon carbide (SiC), and the temperature measured member 65T is buriedin a concave portion formed on a bottom surface. The temperaturemeasured member 65T is formed of, for example, silicon (Si), quartz, orsapphire, has parallel top and bottom surfaces, and is mirror-likefinished. A thickness of the temperature measured member 65T is, forexample, equal to or more than 50 μm. When the thickness is lower than50 μm, an interference waveform based on a reflection light from the topsurface and an interference waveform based on a reflection light fromthe bottom surface overlap each other, and thus a difference betweeninterference locations of the two interference waveforms becomesunclear, thereby increasing an error. A heat transfer sheet 65 e isdisposed on a contact portion of the top surface of the temperaturemeasured member 65T and an inner surface of the concave portion of thefocus ring 65, and thus thermal integration may be promoted.

Like in the above embodiment, temperature measurement of the focus ring65 having such a configuration is performed by irradiating alow-coherence light from the collimator 38 perpendicularly to thetemperature measured member 65T buried in the focus ring 65, receivingreflection lights from the top and bottom surfaces of the temperaturemeasured member 65T, obtaining a temperature of the temperature measuredmember 65T like in the above embodiment, and determining the temperatureof the temperature measured member 65T via the temperature of the focusring 65.

According to the present embodiment, since the temperature measuredmember 65T formed of translucent Si is buried in the focus ring 65 andoperates as a temperature measured portion, where the temperaturemeasured member 65T has parallel top and bottom surfaces to which amirror-like finishing is performed, an accurate temperature may bemeasured even if the focus ring 65 has been worn away. In other words,since the temperature measured member 65T is buried in the bottomsurface of the focus ring 65, the top surface of the temperaturemeasured member 65T is covered by the focus ring 65. Accordingly, adegree of parallelization of the top and bottom surfaces of thetemperature measured member 65T is maintained without an effect ofabrasion, and thus accurate temperature measurement is possible.

In the present embodiment, the heat transfer sheet 65 e may be disposedon an entire contact surface of the temperature measured member 65T anda wall surface of the concave portion of the focus ring 65. Accordingly,thermal integration of the temperature measured member 65T and the focusring 65 is improved, and thus accurate temperature measurement ispossible.

Alternatively, instead of forming the heat transfer sheet 65 e, a gaspath may be formed in the focus ring 65, and a heat transfer gas, forexample, helium (He) gas, may be distributed to the contact portion ofthe focus ring 65 and the temperature measured member 65T. At this time,thermal integration of the temperature measured member 65T and the focusring 65 may be also obtained.

Next, a modified example of the second embodiment will be described.

FIG. 8 is a cross-sectional view schematically showing a structure of afocus ring 75 according to a modified example of the second embodiment.

In FIG. 8, the focus ring 75 is different from the focus ring 65 of FIG.7 in that the focus ring 75 is formed of silicon (Si), and a lightpenetration gap 75 f is formed on a part of a heat transfer sheet 75 edisposed on a contact surface of a top surface of a temperature measuredmember 75T and an inner surface of a concave portion of the focus ring75.

In the focus ring 75 having such a configuration, temperaturemeasurement is performed like in the above embodiments, and alow-coherence light is irradiated toward the light penetration gap 75 f.

In the modified example of the present embodiment, a temperature of thefocus ring 75 formed of silicon may be accurately measured without aneffect of abrasion. Also, by forming the light penetration gap 75 f onthe heat transfer sheet 75 e, abrasion of the focus ring 75 may bemonitored.

Next, a third embodiment of the present invention will be described.

FIG. 9 is a cross-sectional view schematically showing a configurationof a focus ring 85 according to a third embodiment of the presentinvention.

In FIG. 9, the focus ring 85 is formed by attaching a temperaturemeasured member 85T formed of silicon (Si) on about half of a bottomsurface of the focus ring 85 formed of silicon carbide (SiC) via a heattransfer sheet 85 e. The temperature measured member 85T has a circleshape concentric with an outer peripheral portion of the focus ring 85,along the outer peripheral portion.

Like each embodiment described above, temperature measurement of thefocus ring 85 having such a configuration is performed by irradiating alow-coherence light to the temperature measured member 85T from thecollimator 38.

In the present embodiment, since the temperature measured member 85T iscovered by the focus ring 85, a temperature of the focus ring 85 may beaccurately measured without an effect of abrasion.

Next, a modified example of the present embodiment will be described.

FIG. 10 is a cross-sectional view schematically showing a configurationof a focus ring 95 according to a modified example of the thirdembodiment.

In FIG. 10, the focus ring 95 is different from the focus ring 85 ofFIG. 9 in that a temperature measured member 95T is formed on an entirebottom surface of the focus ring 95.

In the modified example of the present embodiment, since the temperaturemeasured member 95T is covered by the focus ring 95 like in the aboveembodiments, a temperature of the focus ring 95 may be accuratelymeasured without an effect of abrasion.

Next, a fourth embodiment of the present invention will be described.

FIG. 11 is a cross-sectional view schematically showing a configurationof a focus ring 105 according to a fourth embodiment of the presentinvention.

According to FIG. 11, in the focus ring 105, an upper outer peripheralportion that is easily worn away is formed of a material having highplasma tolerance, for example, silicon carbide (SiC), and other portionsare formed of, for example, silicon (Si). In other words, the focus ring105 includes a silicon carbide layer 105 g forming the upper outerperipheral portion that is easily worn away, and a silicon layer 105Tforming the other portions, wherein a heat transfer sheet 105 e isdisposed on an attached surface thereof. The silicon layer 105T as abottom surface coated by the silicon carbide layer 105 g as a topsurface becomes a temperature measured portion.

Temperature measurement of the focus ring 105 having such aconfiguration is performed by, like in each embodiment described above,irradiating a low-coherence light to the silicon layer 105T from thecollimator 38.

In the present embodiment, a temperature of the focus ring 105 may beaccurately measured without an effect of abrasion, like in each of theabove embodiments.

Next, a modified example of the present embodiment will be described.

FIG. 12 is a cross-sectional view schematically showing a configurationof a focus ring 115 according to a modified example of the fourthembodiment.

In FIG. 12, the focus ring 115 is used when an inner peripheral portionis easily worn away. A layer formed of a material having high plasmatolerance, for example, a silicon carbide layer 115 g, is disposedmainly on an inner peripheral portion of a top surface of the focus ring115, and other portions are formed of a silicon layer 115T. The siliconlayer 115T as a bottom surface coated by the silicon carbide layer 115 gas a top surface becomes a temperature measured portion.

According to the modified example of the present embodiment, atemperature of the focus ring 115 may be accurately measured without aneffect of abrasion, like in the above embodiments.

According to the present invention, a temperature of a component in aprocessing chamber can be accurately measured by using a temperaturemeasuring apparatus using an interference of low-coherence light even ifa front surface and a rear surface of the component is no longerparallel due to abrasion or the like, because a measurement light isirradiated to a surface of a temperature measured portion at anonabrasive surface side, where the temperature measured portionincludes the surface at the nonabrasive surface side and a surface at anabrasive surface side, which is not worn away by being coated by acoating portion, and a temperature of the temperature measured portionis obtained based on an optical path length difference of two reflectionlights reflected from the surface at the nonabrasive surface side andthe surface at the abrasive surface.

While this invention has been particularly shown and described withreference to exemplary embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims.

1. A component in a processing chamber of a substrate processingapparatus, wherein a temperature of the component is measured, thecomponent comprising: an abrasive surface which is exposed to anabrasive atmosphere and a nonabrasive surface which is not exposed tothe abrasive atmosphere; a temperature measured portion including asurface at the abrasive surface side and a surface at the nonabrasivesurface side, which are parallel to each other; and a coating portionwhich coats the surface of the temperature measured portion at theabrasive surface side.
 2. The component of claim 1, wherein thetemperature measured portion is a thin-walled portion corresponding to aconcave portion formed on the abrasive surface, and a mirror-likefinishing is performed on each of a surface of the thin-walled portionat the abrasive surface side and a surface of the thin-walled portion atthe nonabrasive surface side.
 3. The component of claim 2, wherein asurface roughening process is performed on a surface of the coatingportion facing the surface of the thin-walled portion at the abrasivesurface side.
 4. The component of claim 2, wherein a heat transfer sheetor a heat transfer gas is disposed at a contact portion of the coatingportion and an inner surface of the concave portion.
 5. The component ofclaim 2 wherein the coating portion is formed of any one of silicon(Si), silicon carbide (SiC), quartz, sapphire, ceramic, alumina (Al₂O₃),and aluminum nitride (AlN).
 6. The component of claim 1, wherein thetemperature measured portion is a temperature measured member insertedto a concave portion formed on the nonabrasive surface of the componentin the processing chamber of the substrate processing apparatus, whereina mirror-like finishing is performed on each of a surface of thetemperature measured member at the abrasive surface side and a surfaceof the temperature measured member at the nonabrasive surface side. 7.The component of claim 6, wherein a surface roughening process isperformed on an inner surface of the concave portion facing the surfaceof the temperature measured member at the abrasive surface side.
 8. Thecomponent of claim 6, wherein a heat transfer sheet or a heat transfergas is disposed at a contact portion of the temperature measured memberand the inner surface of the concave portion.
 9. The component of claim6, wherein the temperature measured member is formed of silicon (Si),quartz, or sapphire.
 10. The component of claim 1, wherein thetemperature measured portion is a part of the component in theprocessing chamber of the substrate processing apparatus, a mirror-likefinishing is performed on each of the surface at the abrasive surfaceside and the surface at the nonabrasive surface side with respect to thepart of the component in the processing chamber of the substrateprocessing apparatus, and the surface at the abrasive surface side, onwhich the mirror-like finishing is performed, is covered by the coatingportion.
 11. The component of claim 1, wherein the temperature measuredportion is a temperature measured member inserted to a cut-out portionformed on the nonabrasive surface of the component in the processingchamber of the substrate processing apparatus, a mirror-like finishingis performed on each of the surface of the temperature measured memberat the abrasive surface side and the surface of the temperature measuredmember at the nonabrasive surface side, and the surface of thetemperature measured member at the abrasive surface side is covered by apart forming the cut-out portion of the component in the processingchamber of the substrate processing apparatus.
 12. The component ofclaim 1, wherein the temperature measured portion is a temperaturemeasured member attached to the nonabrasive surface of the component inthe processing chamber of the substrate processing apparatus, amirror-like finishing is performed on each of the surface of thetemperature measured member at the abrasive surface side and the surfaceof the temperature measured member at the nonabrasive surface side, andthe surface of the temperature measured member at the abrasive surfaceside is covered by the component in the processing chamber of thesubstrate processing apparatus.
 13. The component of claim 12, whereinthe temperature measured member has a stepped portion comprising a thickplate portion and a thin plate portion, a surface of the thin plateportion at the abrasive surface side and a surface of the thin plateportion at the nonabrasive surface side are parallel to each other, amirror-like finishing is performed on each of the surfaces of the thinplate portion, and the surface of the thin plate portion at the abrasivesurface side is covered by a part of the component in the processingchamber of the substrate processing apparatus.
 14. The component ofclaim 12, wherein the temperature measured member comprises a steppedportion comprising a thick plate portion and a thin plate portion, asurface of the thick plate portion at the abrasive surface side and asurface of the thick plate portion at the nonabrasive surface side areparallel to each other, a mirror-like finishing is performed on each ofthe surfaces of the thick plate portion, and the surface of the thickplate portion at the abrasive surface side is covered by a part of thecomponent in the processing chamber of the substrate processingapparatus.
 15. The component of claim 1, wherein the component in theprocessing chamber of the substrate processing apparatus is any one of afocus ring, an upper electrode, a lower electrode, an electrodeprotecting member, an insulator, an insulation ring, an observationwindow, a bellows cover, a baffle plate, and a deposhield.
 16. A methodof measuring a temperature of a component in a processing chamber of asubstrate processing apparatus by using an interference of alow-coherence light, the method comprising: irradiating a measurementlight to a surface of a temperature measured portion at a nonabrasivesurface side, wherein the temperature measured portion is formed in thecomponent in the processing chamber of the substrate processingapparatus, the component comprising an abrasive surface exposed to anabrasive atmosphere and the nonabrasive surface not exposed to theabrasive atmosphere, a surface of the temperature measured portion atthe abrasive surface side and the surface of the temperature measuredportion at the nonabrasive surface side are parallel to each other, andthe surface of the temperature measured portion at the abrasive surfaceside is covered by a coating portion; receiving a reflection light ofthe measurement light reflected from the surface of the temperaturemeasured portion at the nonabrasive surface side, and a reflection lightof the measurement light reflected from the surface of the temperaturemeasured portion at the abrasive surface side; detecting an optical pathlength difference between the two received reflection lights; andcalculating a temperature of the temperature measured portion based onthe detected optical path length difference and a pre-obtainedrelationship between the optical path length difference and atemperature of the temperature measured portion.
 17. The method of claim16, wherein the temperature measured portion is a thin-walled portioncorresponding to a concave portion formed on the abrasive surface of thecomponent in the processing chamber of the substrate processingapparatus, and a mirror-like finishing is performed on each of a surfaceof the thin-walled portion at the abrasive surface side and a surface ofthe thin-walled portion at the nonabrasive surface side.
 18. The methodof claim 17, wherein a surface roughening process is performed on asurface of the coating portion facing the surface of the thin-walledportion at the abrasive surface side.
 19. The method of claim 17,wherein a heat transfer sheet or a heat transfer gas is disposed at acontact portion of the coating portion and an inner surface of theconcave portion.
 20. The method of claim 17, wherein the coating portionis formed of any one of silicon (Si), silicon carbide (SiC), quartz,sapphire, ceramic, alumina (Al₂O₃), and aluminum nitride (AlN).
 21. Themethod of claim 16, wherein the temperature measured portion is atemperature measured member inserted to a concave portion formed on thenonabrasive surface of the component in the processing chamber of thesubstrate processing apparatus, and a mirror-like finishing is performedon each of a surface of the temperature measured member at the abrasivesurface side and a surface of the temperature measured member at thenonabrasive surface side.
 22. The method of claim 21, wherein a surfaceroughing process is performed on an inner surface of the concave portionfacing the surface of the temperature measured member at the abrasivesurface side.
 23. The method of claim 21, wherein a heat transfer sheetor a heat transfer gas is disposed at a contact portion of thetemperature measured member and the inner surface of the concaveportion.
 24. The method of claim 21, wherein the temperature measuredmember is formed of silicon (Si), quartz, or sapphire.
 25. The method ofclaim 16, wherein the component in the processing chamber of thesubstrate processing apparatus is any one of a focus ring, an upperelectrode, a lower electrode, an electrode protecting member, aninsulator, an insulation ring, an observation window, a bellows cover, abaffle plate, and a deposhield.